Disclosed is a nonglaring mirror which is an electrochromic device in principle. The mirror comprises a transparent front substrate laid with a transparent first electrode film, a back substrate laid with a second electrode film which is opposite and spaced from the first electrode film, first and second electrochromic layers formed on the first and second electrode films, respectively, and an electrolyte liquid which fills up the space between the two substrates. A reflecting surface is provided by using a transparent sheet as the back substrate and coating the rear surface of the back substrate with a reflecting metal film, or by using a reflecting metal film as the second electrode film. One of the first and second electrochromic layers is formed of a polymer of a conjugated compound, such as substituted or unsubstituted triphenylamine, and the other is formed of a transition metal oxide such as WO.sub.3. In the initial state both the first and second electrochromic layers are colorless and transparent. For coloration, the conjugated polymer layer is oxidized and the transition metal oxide layer is reduced. In the colored state the reflectance of the mirror becomes 7-15% and is controllable.